import React from 'react';
import { render, screen, fireEvent } from '@testing-library/react';
import ExperimentCalendar from '../src/components/ExperimentCalendar';

const mockNavigate = jest.fn();
jest.mock('react-router-dom', () => ({
  useNavigate: () => mockNavigate,
}));

const EXP_ID = 'aaaaaaaa-0000-0000-0000-000000000001';

const TEMPLATE = [
  { fieldId: '00000000-0000-0000-0000-000000000002', key: 'vitals',   label: 'Vitals',   active: true,  builtin: true  },
  { fieldId: 'ww000000-0000-0000-0000-000000000099', key: 'weights',  label: 'Weights',  active: true,  builtin: false },
  { fieldId: 'zz000000-0000-0000-0000-000000000001', key: 'notes',    label: 'Notes',    active: false, builtin: true  },
];

function todayStr() {
  const d = new Date();
  return `${d.getFullYear()}-${String(d.getMonth() + 1).padStart(2, '0')}-${String(d.getDate()).padStart(2, '0')}`;
}

function makeStatus(animalId, date, customFields = {}, vitals = null) {
  return {
    id: `s-${animalId}-${date}`,
    animal_id: animalId,
    date: `${date}T00:00:00.000Z`,
    experiment_description: null,
    vitals,
    treatment: null,
    notes: null,
    custom_fields: customFields,
    analysis_summary: null,
  };
}

beforeEach(() => {
  jest.clearAllMocks();
});

// ── Rendering ──────────────────────────────────────────────────────────────────

describe('ExperimentCalendar rendering', () => {
  it('renders the current month and year', () => {
    render(<ExperimentCalendar experimentId={EXP_ID} template={TEMPLATE} allStatuses={[]} />);
    const now = new Date();
    const monthLabel = now.toLocaleString('en-US', { month: 'long', year: 'numeric' });
    expect(screen.getByText(monthLabel)).toBeInTheDocument();
  });

  it('renders day-of-week headers', () => {
    render(<ExperimentCalendar experimentId={EXP_ID} template={TEMPLATE} allStatuses={[]} />);
    for (const d of ['Sun', 'Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat']) {
      expect(screen.getByText(d)).toBeInTheDocument();
    }
  });

  it('renders the field selector with active template fields only', () => {
    render(<ExperimentCalendar experimentId={EXP_ID} template={TEMPLATE} allStatuses={[]} />);
    const options = screen.getAllByRole('option').map((o) => o.textContent);
    expect(options).toContain('Vitals');
    expect(options).toContain('Weights');
    expect(options).not.toContain('Notes'); // inactive
  });
});

// ── Default field selection ────────────────────────────────────────────────────

describe('default field selection', () => {
  it('defaults to the field whose label contains "weight"', () => {
    render(<ExperimentCalendar experimentId={EXP_ID} template={TEMPLATE} allStatuses={[]} />);
    expect(screen.getByTestId('field-select')).toHaveValue('ww000000-0000-0000-0000-000000000099');
  });

  it('defaults to first field if none contains "weight"', () => {
    const noWeightTemplate = [
      { fieldId: 'ff000000-0000-0000-0000-000000000001', key: 'treatment', label: 'Treatment', active: true, builtin: true },
      { fieldId: 'ff000000-0000-0000-0000-000000000002', key: 'vitals',    label: 'Vitals',    active: true, builtin: true },
    ];
    render(<ExperimentCalendar experimentId={EXP_ID} template={noWeightTemplate} allStatuses={[]} />);
    expect(screen.getByTestId('field-select')).toHaveValue('treatment');
  });
});

// ── Count badges (computed from allStatuses) ───────────────────────────────────

describe('count badges', () => {
  it('shows a count badge for a day where the selected field is non-empty', () => {
    const dateStr = todayStr();
    const statuses = [
      makeStatus('a1', dateStr, { 'ww000000-0000-0000-0000-000000000099': '325' }),
      makeStatus('a2', dateStr, { 'ww000000-0000-0000-0000-000000000099': '310' }),
    ];
    render(<ExperimentCalendar experimentId={EXP_ID} template={TEMPLATE} allStatuses={statuses} />);
    expect(screen.getByTestId(`count-${dateStr}`)).toHaveTextContent('2');
  });

  it('does not show count badge on days with no data', () => {
    render(<ExperimentCalendar experimentId={EXP_ID} template={TEMPLATE} allStatuses={[]} />);
    expect(screen.queryByTestId(`count-${todayStr()}`)).not.toBeInTheDocument();
  });

  it('shows a count badge for builtin field (vitals)', () => {
    const dateStr = todayStr();
    const statuses = [makeStatus('a1', dateStr, {}, 'HR 72')];
    render(<ExperimentCalendar experimentId={EXP_ID} template={TEMPLATE} allStatuses={statuses} />);
    fireEvent.change(screen.getByTestId('field-select'), { target: { value: 'vitals' } });
    expect(screen.getByTestId(`count-${dateStr}`)).toHaveTextContent('1');
  });

  it('recomputes counts after field change', () => {
    const dateStr = todayStr();
    const statuses = [makeStatus('a1', dateStr, {}, 'HR 72')];
    render(<ExperimentCalendar experimentId={EXP_ID} template={TEMPLATE} allStatuses={statuses} />);
    // Default is weights — no badge
    expect(screen.queryByTestId(`count-${dateStr}`)).not.toBeInTheDocument();
    // Switch to vitals — badge appears
    fireEvent.change(screen.getByTestId('field-select'), { target: { value: 'vitals' } });
    expect(screen.getByTestId(`count-${dateStr}`)).toHaveTextContent('1');
  });
});

// ── Month navigation ──────────────────────────────────────────────────────────

describe('month navigation', () => {
  it('moves to the previous month on ‹ click', () => {
    render(<ExperimentCalendar experimentId={EXP_ID} template={TEMPLATE} allStatuses={[]} />);
    const now  = new Date();
    const prev = new Date(now.getFullYear(), now.getMonth() - 1, 1);
    const prevLabel = prev.toLocaleString('en-US', { month: 'long', year: 'numeric' });
    fireEvent.click(screen.getByLabelText('Previous month'));
    expect(screen.getByText(prevLabel)).toBeInTheDocument();
  });

  it('moves to the next month on › click', () => {
    render(<ExperimentCalendar experimentId={EXP_ID} template={TEMPLATE} allStatuses={[]} />);
    const now  = new Date();
    const next = new Date(now.getFullYear(), now.getMonth() + 1, 1);
    const nextLabel = next.toLocaleString('en-US', { month: 'long', year: 'numeric' });
    fireEvent.click(screen.getByLabelText('Next month'));
    expect(screen.getByText(nextLabel)).toBeInTheDocument();
  });
});

// ── Day click navigation ──────────────────────────────────────────────────────

describe('day click navigation', () => {
  it('navigates to the day view with field param when a day with data is clicked', () => {
    const dateStr = todayStr();
    const statuses = [
      makeStatus('a1', dateStr, { 'ww000000-0000-0000-0000-000000000099': '325' }),
    ];
    render(<ExperimentCalendar experimentId={EXP_ID} template={TEMPLATE} allStatuses={statuses} />);
    fireEvent.click(screen.getByTestId(`day-${dateStr}`));
    expect(mockNavigate).toHaveBeenCalledWith(
      `/experiments/${EXP_ID}/day/${dateStr}?field=ww000000-0000-0000-0000-000000000099`,
    );
  });

  it('does not navigate when clicking a day without data (button is disabled)', () => {
    render(<ExperimentCalendar experimentId={EXP_ID} template={TEMPLATE} allStatuses={[]} />);
    const dayBtn = screen.getByTestId(`day-${todayStr()}`);
    expect(dayBtn).toBeDisabled();
    fireEvent.click(dayBtn);
    expect(mockNavigate).not.toHaveBeenCalled();
  });

  it('includes the currently selected field in the navigation URL', () => {
    const dateStr = todayStr();
    const statuses = [makeStatus('a1', dateStr, {}, 'HR 72')];
    render(<ExperimentCalendar experimentId={EXP_ID} template={TEMPLATE} allStatuses={statuses} />);
    // Switch to vitals field first
    fireEvent.change(screen.getByTestId('field-select'), { target: { value: 'vitals' } });
    fireEvent.click(screen.getByTestId(`day-${dateStr}`));
    expect(mockNavigate).toHaveBeenCalledWith(
      `/experiments/${EXP_ID}/day/${dateStr}?field=vitals`,
    );
  });

  it('navigates with no field param when selectedField is null (no active fields)', () => {
    const emptyTemplate = [];
    render(<ExperimentCalendar experimentId={EXP_ID} template={emptyTemplate} allStatuses={[]} />);
    // No days have data with empty template, so nothing to click — just verify no crash
    expect(screen.queryByTestId(`count-${todayStr()}`)).not.toBeInTheDocument();
  });
});